A pressure sensor

Abstract

This utility model discloses a pressure sensor, which includes: a first housing; a second housing having a channel extending through it; a pressure-sensitive element for sensing pressure; and a sealing ring, wherein when the first housing and the second housing are assembled together, the pressure-sensitive element and the sealing ring are pressed between the first housing and the second housing, and the sealing ring surrounds a first opening of the channel and is pressed between the pressure-sensitive element and the second housing, so that fluid cannot flow through the gap between the pressure-sensitive element and the second housing.

Description

Technical Field

[0001] This utility model relates to the field of pressure sensing, and more particularly to a pressure sensor. Background Technology

[0002] Pressure sensors, as a crucial sensing element, play a vital role in numerous fields such as industrial automation, automotive electronics, aerospace, and medical equipment. In industrial production processes, they monitor the pressure within pipelines, tanks, and other equipment in real time, ensuring the safety and stability of the production process. In automotive engine management systems, pressure sensors precisely regulate fuel injection pressure to improve combustion efficiency. In the aerospace field, they are involved in measuring critical parameters such as aircraft altitude and speed. In medical equipment, ventilators and blood pressure monitors rely on their accurate pressure monitoring to ensure patient safety during treatment.

[0003] Currently, commonly used pressure sensors have relatively complex structures. They typically consist of multiple components, such as a sensing element, a signal processing circuit, and a housing. The sensing element generally includes a pressure-sensitive element and a corresponding conversion circuit, used to convert the pressure signal into an electrical signal. The signal processing circuit is responsible for amplifying, filtering, and performing analog-to-digital conversion on the electrical signal output by the sensing element to meet the requirements of subsequent data acquisition and control. The housing not only needs to provide mechanical protection for the internal components but also needs to have good sealing properties to prevent external environmental factors from affecting the sensor's performance.

[0004] However, this structure results in a large number of product components and poor stability. On the one hand, numerous components mean more assembly steps and connection points during production, each of which is prone to errors or malfunctions, increasing the overall risk of failure. For example, poor welding quality between the sensing component and the signal processing circuit can lead to unstable signal transmission, resulting in interruptions or distortions. On the other hand, the inter-component coordination requirements are high; even a slight change in the performance of one component can trigger a chain reaction, affecting the stability and accuracy of the entire sensor. Taking the sealing process as an example, the sensing component of a traditional pressure sensor needs to be installed on a carrier before being assembled with the upper housing. This complex structure results in numerous sealing points, and failure of any one of these points can allow external media to seep in, interfering with the normal operation of the pressure-sensitive element, shortening the sensor's lifespan, and consequently affecting its reliability and stability. This makes it difficult to meet the high-precision, high-reliability pressure measurement requirements of modern industrial and other application scenarios. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model aims to provide a pressure sensor that achieves comprehensive advantages such as low cost, high efficiency, fast response, high reliability, and small size, significantly outperforming existing pressure sensors with complex multi-stage structures.

[0006] The technical solution of this utility model is implemented as follows:

[0007] This utility model embodiment provides a pressure sensor, the pressure sensor comprising:

[0008] First shell;

[0009] A second housing, wherein the second housing has a channel through which the second housing passes;

[0010] Pressure-sensitive element used to sense pressure;

[0011] Sealing ring,

[0012] When the first housing and the second housing are assembled together, the pressure-sensitive element and the sealing ring are pressed between the first housing and the second housing. The sealing ring surrounds the first opening of the channel and is pressed between the pressure-sensitive element and the second housing, so that fluid cannot flow through the gap between the pressure-sensitive element and the second housing.

[0013] In some examples, the first housing has a recess in which the pressure-sensitive element is fitted.

[0014] In some examples, the second housing is formed with a groove in which the sealing ring is fitted.

[0015] In some examples, the first housing and the second housing are assembled together in a nested manner.

[0016] In some examples, the second housing is formed with a columnar protrusion, and a second opening of the channel is formed on the end face of the protrusion.

[0017] In some examples, the outer peripheral surface of the protrusion is formed with threads.

[0018] In some examples, the pressure-sensitive element is rectangular, square, circular, or polygonal.

[0019] In some examples, the pressure-sensitive element is a capacitive pressure-sensitive element or a resistive pressure-sensitive element.

[0020] In some examples, the pressure-sensitive element has connection terminals for electrical connection to a circuit board.

[0021] In some examples, the circuit board is fitted into the recess.

[0022] This utility model provides a pressure sensor with fewer components, reduced to four: two housings, a sensing element, and a sealing ring. This significantly reduces material and quality control costs. Positioning and sealing are achieved in a single axial compression step, shortening assembly time and improving yield. The channel opening directly faces the sensing surface, resulting in an extremely short path and faster response. The shortened structure and reduced diameter make it easier to install in space-constrained environments. Controlled compression of only one sealing ring significantly reduces the risk of leakage. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of a pressure sensor according to an embodiment of the present invention. Detailed Implementation

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] To fulfill the basic function of "sensing-processing-output," existing pressure sensors often break down the functions of sensing, conversion, amplification, sealing, and installation into multiple independent components: the sensing element is first fixed to a transition carrier, which is then fixed to the housing; the signal processing board is externally connected in a flexible or rigid manner; and finally, multiple sealing rings or colloids are used to seal the components layer by layer. The more components there are, the longer the assembly chain becomes, and each additional mating surface represents another potential failure point. Any dimensional tolerance, weld void, or seal aging will be amplified step by step to output drift, signal fluctuations, or even complete failure. The result is: large size, high cost, and consistently limited reliability.

[0026] In view of this, see Figure 1 This utility model provides a pressure sensor 1, which may include:

[0027] First shell 10;

[0028] The second housing 20 has a channel 21 through which it passes;

[0029] Pressure-sensitive element 30 for sensing pressure;

[0030] Sealing ring 40,

[0031] When the first housing 10 and the second housing 20 are assembled together, the pressure-sensitive element 30 and the sealing ring 40 are pressed between the first housing 10 and the second housing 20. The sealing ring 40 surrounds the first opening 21A of the channel 21 and is pressed between the pressure-sensitive element 30 and the second housing 20, so that fluid cannot flow through the gap between the pressure-sensitive element 30 and the second housing 20.

[0032] Traditional solutions require a carrier, adapter plate, multiple sealing rings, and numerous fasteners. This embodiment, however, requires only four components: the first housing 10, the second housing 20, the pressure-sensitive element 30, and the sealing ring 40, to complete all functions. This significant reduction in the number of parts directly lowers material procurement, warehousing, and quality inspection costs, while also reducing potential failure points and significantly improving overall reliability. The production line only requires a single axial pressing step to lock the first housing 10 and the second housing 20 together. The pressure-sensitive element 30 and the sealing ring 40 are simultaneously positioned and pressed, forming a sealed space enclosed by the pressure-sensitive element 30, the sealing ring 40, and the second housing 20. This eliminates the need for repeated alignment, welding, or gluing, shortening the assembly cycle time, reducing labor and equipment investment, and significantly improving first-pass yield due to fewer assembly error sources. The first opening 21A of channel 21 directly faces the sensing surface of pressure-sensitive element 30, separated only by a sealing ring 40. The path of fluid from entering channel 21 to acting on pressure-sensitive element 30 is extremely short, eliminating the delay caused by the multi-stage transition of "carrier-transfer plate-housing" in traditional structures. Because the transition carrier and lengthy sealing chain are eliminated, pressure-sensitive element 30 directly becomes part of the housing sealing interface, shortening the overall axial dimension of the sensor and correspondingly reducing its outer diameter, making it easier to arrange and maintain in scenarios with limited installation space. The seal relies solely on a single axially compressed sealing ring 40, the compression of which is precisely controlled by the fit between the first housing 10 and the second housing 20, avoiding the risk of leakage caused by asynchronous aging of multiple sealing rings.

[0033] In embodiments according to this utility model, see Figure 1 The first housing 10 has a recess 11, and the pressure-sensitive element 30 is assembled in the recess 11.

[0034] The contour of the recess 11 matches the shape of the pressure-sensitive element 30. During production, the pressure-sensitive element 30 is simply placed in the recess 11, the second housing 20 is then placed on top, and axially pressed together once. This simplifies the process from "multi-step positioning + multiple checks" to "one placement and one pressing," significantly shortening the assembly cycle. Furthermore, the depth and sidewall tolerances of the recess 11 can be controlled within a small range, minimizing the positional difference of the pressure-sensitive element 30 each time it falls in, ensuring consistent compression of the sealing ring 40, thus minimizing the risk of seal failure due to misalignment. The recess 11 is directly machined onto the first housing 10, with the pressure-sensitive element 30 "sunk" into it. This not only eliminates the space occupied by external positioning structures but also reduces the overall height of the sensor, which is particularly advantageous for installation in space-constrained pipelines or valve bodies. The elimination of additional positioning fixtures during assembly reduces the steps of tooling design, machining, and periodic calibration. The single machining cost of the recess 11 can replace the positioning fixture, resulting in significant long-term economic benefits.

[0035] In embodiments according to this utility model, see Figure 1 The second housing 20 has a groove 22, and the sealing ring 40 is assembled in the groove 22.

[0036] The cross-sectional shape of the groove 22 matches the cross-section of the sealing ring 40. Before assembling the first housing 10 and the second housing 20, the sealing ring 40 only needs to be lightly pressed into the groove 22 to self-lock. Subsequently, when the first housing 10 and the second housing 20 are axially closed, the groove 22 moves with the second housing 20 as a whole, and the sealing ring 40 always remains within the groove 22, without the need for manual realignment or the use of locating pins, guide sleeves, or other auxiliary devices. Since the groove 22 is directly opened in the second housing 20, the sealing ring 40 is automatically guided and centered by the side wall of the groove 22 at the moment of pressing, eliminating local overpressure or underpressure caused by manual placement misalignment, thus reducing the sealing failure rate. By eliminating the need for a dedicated sealing positioning fixture, not only are the costs of fixture design, processing, and periodic calibration saved, but also the downtime maintenance caused by fixture wear is avoided. A single machining of the groove 22 can permanently replace the fixture, resulting in a significant reduction in long-term production costs.

[0037] In embodiments according to this utility model, see Figure 1 The first housing 10 and the second housing 20 are assembled together in a nested manner.

[0038] As in Figure 1As shown, the outer cylindrical surface of the first housing 10 and the inner cylindrical surface of the second housing 20 form a precision clearance fit. During assembly, the two housings automatically align coaxially, and the centerline deviation between the pressure-sensitive element 30, the sealing ring 40, and the channel 21 is small, achieving high-precision assembly without the need for additional locating pins or fixtures. The nested cylindrical surfaces ensure that the locking force of the first housing 10 and the second housing 20 is evenly distributed along 360°, and the compression ratio of the sealing ring 40 varies little, avoiding local overpressure aging and extending its lifespan. The nested structure has a "self-compensation" effect on axial clamping force fluctuations, maintaining coaxiality and end-face fit. The nested design integrates the three functions of "guidance-sealing-protection" into the same cylindrical section, shortening the overall length of the sensor and reducing its outer diameter, making it more suitable for compact installation environments.

[0039] Specifically, such as in Figure 1 As shown, after the first housing 10 and the second housing 20 are nested together, the upper edge of the second housing 20 is riveted onto the corresponding stepped mating part of the first housing 10, thereby realizing the riveted connection between the two.

[0040] In embodiments according to this utility model, see Figure 1 The second housing 20 has a columnar protrusion 23, and the second opening 21B of the channel 21 is formed on the end face of the protrusion 23.

[0041] In this way, the protrusion 23 forms a natural pressure tap, shortening the pressure transmission path. Specifically, the outer diameter of the protrusion 23 can be smaller than the body of the second housing 20, allowing it to be directly inserted into narrow pipe openings or cavities. This brings the second opening 21B close to the source of the measured medium, and the pressure reaches the pressure-sensitive element 30 directly through the second opening 21B, channel 21, and first opening 21A. The measured pressure rise time is shortened, and the pulsating signal shows no significant attenuation. The outer wall of the protrusion 23 can be designed with standard threads, quick-connect fittings, or welded steps. On-site, it only needs to be screwed into / inserted into the pipeline under test to complete the sealing and fixation, eliminating the need for additional adapters and transition flanges required by traditional solutions, reducing installation time and the number of leakage points. Because the protrusion 23 is in zero-distance contact with the measured environment, the temperature gradient and dead zone volume are minimized. Under alternating high and low temperature conditions, the zero-point drift is small, and the repeatability error is small, which is significantly better than solutions requiring long pressure taps. The protrusion 23 is integrally formed with the second housing 20 without any additional protrusions. The overall axial length is shorter than that of a traditional external thread pressure tap, and it can still be installed in any direction at 180° in dense spaces such as engine blocks and brake modules.

[0042] In an embodiment according to the present invention, the outer peripheral surface of the protrusion 23 is formed with threads.

[0043] The thread specification can be designed according to general pipe threads. On-site installation of pressure sensor 1 can be completed with only a regular wrench or even by hand. Quick-connect fittings require snap ring pliers, and welding requires a welding torch and power supply. In comparison, the screwing operation has the lowest dependence on tools and environment. Threaded connections can be unscrewed in reverse during maintenance, and pressure sensor 1 remains intact. Quick-connect fittings are prone to snap ring fatigue after repeated insertion and removal, and welding requires cutting or high-temperature removal, both of which can cause irreversible damage to the pipeline or sensor. The thread is directly machined on the protrusion 23, resulting in a short processing time per piece. Unlike quick-connect fittings, there is no need for additional injection-molded metal clips, and the beveling, shielding gas, and post-processing steps required for welding are also eliminated, resulting in lower overall costs.

[0044] Additionally, as in Figure 1 As shown, a sealing ring may also be provided on the outer periphery of the protrusion 23 to ensure a seal between the pressure sensor 1 and, for example, the pipeline to be tested.

[0045] In embodiments according to the present invention, the pressure-sensitive element 30 is rectangular, square, circular, or polygonal.

[0046] A circular pressure-sensitive element 30 can achieve isotropic stress concentration, while a rectangular / square shape facilitates the placement of more Wheatstone bridge resistors at the chip level, improving sensitivity. Polygonal shapes (such as hexagons) maintain high sensitivity while chamfering the edges to suppress microcrack propagation and extend fatigue life. Regardless of the planar shape of the pressure-sensitive element 30, its outer edge always falls within the annular compression zone of the sealing ring 40. The recess 11 of the first housing 10 and the groove 22 of the second housing 20 do not need to be re-molded according to shape changes; only the contour tolerance needs to be adjusted to share the production line, reducing mold costs.

[0047] In embodiments of the present invention, the pressure-sensitive element 30 may be a capacitive pressure-sensitive element or a resistive pressure-sensitive element.

[0048] In this embodiment, the pressure-sensitive element 30 can be either capacitive or resistive. Both technologies share the first housing 10, the second housing 20, and the sealing structure, but each brings different performance advantages. Specifically, the capacitive type uses the change in electrode spacing to generate capacitance displacement, resulting in high sensitivity and low temperature drift. It can achieve ultra-high precision in the low-pressure range of 0–1 MPa, making it suitable for medical and pneumatic precision control. The resistive type outputs millivolt-level signals through the piezoresistive effect, has a wide linear range, and maintains high precision within the range of 0–20 MPa, meeting the high-pressure scenarios such as automotive engine oil and common rail fuel.

[0049] In embodiments according to this utility model, see Figure 1 The pressure-sensitive element 30 has connection terminals for electrical connection with the circuit board 50.

[0050] In embodiments according to this utility model, see Figure 1 The circuit board 50 is assembled in the recess 11.

[0051] In this case, similar to the pressure-sensitive element 30, when the first housing 10 and the second housing 20 are axially closed, the circuit board 50 can move together with the first housing 10 without any additional clamps to position the circuit board 50, thus shortening the assembly cycle.

[0052] Circuit board 50 can be a flexible circuit board, thereby providing flexibility in the structural design of pressure sensor 1. It is understood that circuit board 50 can also be other types of circuit boards, such as rigid circuit boards.

[0053] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A pressure sensor, characterized by include: First shell; A second housing, wherein the second housing has a channel through which the second housing passes; Pressure-sensitive element used to sense pressure; Sealing ring, When the first housing and the second housing are assembled together, the pressure-sensitive element and the sealing ring are pressed between the first housing and the second housing. The sealing ring surrounds the first opening of the channel and is pressed between the pressure-sensitive element and the second housing, so that fluid cannot flow through the gap between the pressure-sensitive element and the second housing.

2. The pressure sensor of claim 1, wherein, The first housing has a recess, in which the pressure-sensitive element is assembled.

3. The pressure sensor according to claim 1 or 2, characterized in that The second housing has a groove, and the sealing ring is fitted into the groove.

4. The pressure sensor according to claim 1 or 2, characterized in that The first housing and the second housing are assembled together in a nested manner.

5. The pressure sensor according to claim 1 or 2, characterized in that The second housing has a columnar protrusion, and the second opening of the channel is formed on the end face of the protrusion.

6. The pressure sensor of claim 5, wherein, The outer peripheral surface of the protrusion is formed with threads.

7. The pressure sensor of claim 1 or 2, wherein, The pressure-sensitive element is rectangular, square, circular, or polygonal.

8. The pressure sensor of claim 2, wherein, The pressure-sensitive element is either a capacitive pressure-sensitive element or a resistive pressure-sensitive element.

9. The pressure sensor of claim 8, wherein, The pressure-sensitive element has connection terminals for electrical connection to a circuit board.

10. The pressure sensor of claim 9, wherein, The circuit board is assembled in the recess.

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